Internet Exchange Points in the United States

Emerald Onion is researching IXPs in the U.S.A. in order to identify areas of priority as it concerns increasing global Tor network capacity by way of putting Tor routers directly on these highly interconnected networks. Putting Tor exit routers in IXPs, for example, may reduce network latency to end points. It may also reduce network hops, potentially minimizing the possibility of third-party surveillance. Emerald Onion envisions a future where the Tor network is composed of much larger and more stable network operators, globally.

Questions

Are there any Tor routers connected to any United States-based IXPs? If so, which ones and who operates them?

Is this IXP friendly to Tor?

What is the organizational structure of this IXP? Such as corporate-run or community-driven, etc.

What qualities of an IXP should impact how meaningful it would be for the Tor network?